A conventional blower may be used for inflating an object, such as a huge toy balloon. The conventional blower 10 is shown in FIGS. 1 and 2 and generally includes a base 11 which is put on the ground and has a recessed area 112 and an inlet 113 is defined in the wall of the recessed area 112. A motor assembly 12 including a motor 121 and a fan device 123 is inserted into the chamber in the base 11 via an open top 111 of the base 11. The motor 121 has lugs 122 which are fixed to recesses 115 on a top of the base 11. A casing 13 is mounted to the top of the base 11 and includes an outlet 131 so as to send air therefrom. It is also noted, that because the position of the inlet 113 is close to the ground, dust and peddles are sucked into the blower and can damage the parts of the fan device 123 and the motor 121. Furthermore, the air sucked from the inlet 113 leaks from the gaps 116 between the fan device 123 and the periphery of the open top 111. The distance between the motor 121 and the base 11 is too small to release the heat from the motor 121 so that the base 11 could be burned. Once the electric power is shut unexpectedly, the air in the huge balloon escapes from the outlet 131 and the inlet 113, and the balloon collapses to trap the kids in the balloon.
The present invention intends to provide a blower that has an anti-back device to prevent the air in the balloon going back from the blower when no electric power is provided.